Lower urinary tract disorders affect the quality of life of millions of men and women in the United States every year. Disorders of the lower urinary tract include overactive bladder, prostatitis and prostadynia, interstitial cystitis, benign prostatic hyperplasia, and, in spinal cord injured patients, spastic bladder.
Overactive bladder is a treatable medical condition that is estimated to affect 17 to 20 million people in the United States. Current treatments for overactive bladder include medication, diet modification, programs in bladder training, electrical stimulation, and surgery. Currently, antimuscarinics (which are subtypes of the general class of anticholinergics) are the primary medication used for the treatment of overactive bladder. This treatment suffers from limited efficacy and side effects such as dry mouth, dry eyes, dry vagina, palpitations, drowsiness, and constipation, which have proven difficult for some individuals to tolerate.
Prostatitis and prostadynia are other lower urinary tract disorders that have been suggested to affect approximately 2–9% of the adult male population (Collins M M, et al., (1998) J. Urology, 159: 1224–1228). Currently, there are no established treatments for prostatitis and prostadynia. Antibiotics are often prescribed, but with little evidence of efficacy. COX-2 selective inhibitors and α-adrenergic blockers and have been suggested as treatments, but their efficacy has not been established. Hot sitz baths and anticholinergic drugs have also been employed to provide some symptomatic relief.
Interstitial cystitis is another lower urinary tract disorder of unknown etiology that predominantly affects young and middle-aged females, although men and children can also be affected. Past treatments for interstitial cystitis have included the administration of antihistamines, sodium pentosanpolysulfate, dimethylsulfoxide, steroids, tricyclic antidepressants and narcotic antagonists, although these methods have generally been unsuccessful (Sant, G. R. (1989) Interstitial cystitis: pathophysiology, clinical evaluation and treatment. Urology Annal 3: 171–196).
Benign prostatic hyperplasia (BPH) is a non-malignant enlargement of the prostate that is very common in men over 40 years of age. Invasive treatments for BPH include transurethral resection of the prostate, transurethral incision of the prostate, balloon dilation of the prostate, prostatic stents, microwave therapy, laser prostatectomy, transrectal high-intensity focused ultrasound therapy and transurethral needle ablation of the prostate. However, complications may arise through the use of some of these treatments, including retrograde ejaculation, impotence, postoperative urinary tract infection and some urinary incontinence. Non-invasive treatments for BPH include androgen deprivation therapy and the use of 5α-reductase inhibitors and α-adrenergic blockers. However, these treatments have proven only minimally to moderately effective for some patients.
Lower urinary tract disorders are particularly problematic for individuals suffering from spinal cord injury. Following spinal cord injury, the bladder is usually affected in one of two ways: 1) “spastic” or “reflex” bladder, in which the bladder fills with urine and a reflex automatically triggers the bladder to empty; or 2) “flaccid” or “non-reflex” bladder, in which the reflexes of the bladder muscles are absent or slowed. Treatment options for these disorders usually include intermittent catheterization, indwelling catheterization, or condom catheterization, but these methods are invasive and frequently inconvenient. Urinary sphincter muscles may also be affected by spinal cord injuries, resulting in an inability of urinary sphincter muscles to relax when the bladder contracts (“dyssynergia”). Traditional treatments for dyssynergia include medications that have been somewhat inconsistent in their efficacy or surgery.
In addition to the lower urinary tract disorders described above, the related genitourinary tract disorders vulvodynia and vulvar vestibulitis have been etiologically and pathologically linked to such lower urinary tract disorders as interstitial cystitis (See Selo-Ojeme et al. (2002) Int. Urogynecol. J. Pelvic Floor Dysfunction 13: 261–2; Metts (2001) Am. Fam. Physician 64: 1199–206; Wesselmann (2001) World J. Urol. 19: 180–5; Parsons et al. (2001) Obstet. Gynecol. 98: 127–32; Heim (2001) Am. Fam. Physician 63: 1535–44; Stewart et al. (1997) J. Reprod. Med. 42: 131–4; Fitzpatrick et al. (1993) Obstet. Gynecol. 81: 860–2). Vulvar vestibulitis syndrome (herein “vulvar vestibulitis”) is a subtype of vulvodynia. Vulvodynia is a complex gynecologic syndrome characterized by unexplained vulvar pain, sexual dysfunction, and psychological disability. It has been estimated that 1.5 million American women may suffer from some degree of vulvodynia. Because of their multiple causes, these disorders can be very difficult to treat. The first-line therapy is typically the treatment of suspected causes by pharmacologic treatment of infections and the discontinued use of suspected irritants and therapeutic agents that may contribute to the problem. Topical anesthetics, corticosteroids, and sex hormones may provide some symptomatic relief. Further treatments may include dietary modifications, physical therapy and biofeedback, use of topical, oral, or injected therapeutic agents, or surgery. Unfortunately, no single treatment works in all patients. Moreover, many of these approaches involve complex medical procedures, significant costs, and/or undesirable side effects.
Because existing therapies and treatments for lower urinary tract disorders and the related genitourinary tract disorders vulvodynia and vulvar vestibulitis in normal and spinal cord injured patients are associated with limitations as described above, new therapies and treatments are therefore desirable.